1. Field of the Invention
This invention relates generally to the stowage of bulky, odd-shaped, uncrated or unstackable units in intermodal shipping containers. It relates particularly to a system for containerized shipment of automobiles.
2. Discussion of the Prior Art
Current systems for transport of imported automobiles generally utilize special purpose ships, railroad cars, and truck-trailers. Individually, these conveyances carry automobiles very efficiently; when viewed as a system however, they have significant drawbacks.
(1) Back haul inefficiency--Specialty car-carrier ships, railcars and truck-trailers are ill-suited for other types of cargo; normally they return empty.
(2) Mode-change inefficiency--Specialized ships used for automobile imports carry thousands of automobiles on each voyage. Imported automobiles must typically make two such mode changes en route, and perhaps one or two more between train and truck. At each one, they are driven off and on the conveyances and are parked in a holding area. Such mode changes are labor intensive, damage-prone and time-consuming.
(3) Transport time inefficiency--Generally, European automobiles exported to the U.S. West Coast and Asian automobiles exported to the East Coast are carried by ship through the Panama Canal. By contrast, containerized cargo is landed on the near coast and shipped by rail to the opposite coast on special container trains, saving a week or more in transit. Time saved is even greater for inland points.
(4) Marketing inefficiency--The excess time lag between manufacture of an import automobile and its receipt by a dealer due to current shipping methods, causes an attendant lag in adjustment of production orders to meet changing market demands.
Despite the substantial savings in handling costs, pilferage, damage and overall transit time normally associated with containerized shipment of freight, automobiles imported in large volume do not use this method. Compared with the current system outlined above, containerized transport of automobiles is too costly because of very poor cube utilization. Using current practice, only two or three automobiles or equivalent-sized vehicles are stowed in a 40-foot intermodal container (see U.S. Pat. No. 3,675,795). As a result, the container neither "weighs out" nor "cubes out". Shipping racks resembling truck-trailer car-carriers, specially made to fit container slots aboard ship, achieve better cube utilization (see U.S. Pat. No. 3,650,416), but because of added expense and lack of back haul cargo, these costly special purpose car-carrier racks have not proved to be a viable alternative for high volume automobile shipments.
In the past, several mechanisms have been developed to increase the number of automobiles stowed longitudinally in container-like conveyances whose dimensions are limited by highway and/or railway length, width and height constraints. All accomplish this by double-decking and/or tilting automobiles at an angle (i.e., half-decking) using various types of supports. These mechanisms may be classified into seven classes, according to the conceptual method of support.
(1) Fixed and/or movable wheel ramps are provided in the conveyance, on which automobiles roll to stowage position and are supported (See U.S. Pat. Nos. 4,455,119; 3,941,064; 3,739,906; 3,650,416; 3,145,043; 2,860,910; 2,838,338, 2,834,631, 2,492,980, 2,009,149 and 1,994,695).
(2) Wheel ramps are provided in the conveyance. After automobiles are rolled onto the ramps, they are inclined to stowage position by integrated hydraulic or mechanical lifting means (see U.S. Pat. Nos. 2,918,326 and 2,617,368).
(3) Inclinable wheel ramp assemblies are provided outside the conveyance (see U.S. Pat. No. 3,675,795). Each assembly is inclined and locked in stowage attitude with one automobile on it. Assemblies are then rolled longitudinally into the conveyance and along its floor to stowage positions.
(4) Various types of adjustable supports are installed inside the conveyance to hold automobiles hoisted to various heights off the stowage floor (see U.S. Pat. Nos. 2,068,460; 2,035,772 and 1,978,287).
(5) Supports similar in concept to those in (4) above but which are movable longitudinally on tracks within the conveyance before automobiles are lifted onto them (see U.S. Pat. Nos. 2,036,212; 2,010,846; 1,969,434, 1,965,525; 1,934,841; 1,869,054; 1,824,983; 1,805,881 and 1,745,982).
(6) Supports similar in concept to those in (5) above but which are movable longitudinally to storage position within the conveyance after automobiles have been lifted onto them (see U.S. Pat. Nos. 1,892,589; 1,749,758 and 1,263,788).
(7) U.S. Pat. No. 1,824,369 is similar in concept, but it incorporates a means for raising one end of an automobile to inclined position within the space before resting it upon supports. The supports can then be moved longitudinally to stowage positions.
None of the prior art mechanisms incorporates the novel concept of vehicle supports which are movable longitudinally along a plurality of longitudinal rails installed at or movable to many heights above the conveyance floor. Nor is any of them intended to carry automobiles tilted not only longitudinally but also transversely so as to maximize cube utilization of the stowage space. All of the mechanisms represent labor intensive methods of stowing automobiles which do not lend themselves to automated loading. In addition, they hold significant potential for cargo damage and personnel injury. All but one of the mechanisms requires positioning an automobile inside the conveyance before lifting it to stowage position.
The method disclosed in U.S. Pat. No. 3,675,795 does allow lifting one end of the automobile to stowage attitude on a supporting rack outside the conveyance, then moving the loaded supporting ramp longitudinally along the stowage floor to stowage position. However, it does not take into consideration multiple level rails and independent pallets and therefore does not allow complete suspension of one automobile over another, being limited to stowage of automobiles with one (or both) pair(s) of wheels at deck level. This lack of flexibility in positioning automobiles limits cube utilization. Practical problems with this approach include the ramp's bulk, cost of returning ramps for reuse, and damage caused by collapsed ramps.
As evidenced by current practice, none of the known methods and apparatus or variations on them served to make containerized shipment cost competitive for large volumes of automobiles.